Implementation of practice change is difficult and large scale implementation is particularly difficult. Among the challenges is the overuse of low value care. Reducing low value care has become a recent focus of VA's quality improvement efforts as evidenced by the VA's creation of a Choosing Wisely Taskforce to recommend how this national initiative can be implemented. Improving medication safety also constitutes an attempt to reduce low value or potentially harmful care. Critical issues of overuse of low value practices and medication safety intersect in overtreatment of diabetes. Specifically, (over)intensive glycemic control increases hypoglycemia risk and morbidity without providing meaningful benefit. Our work indicates that among patients with diabetes who are at high risk for hypoglycemia - due to use of specific hypoglycemic agents, age, and/or significant comorbidities - up to 50% are potentially overtreated, as defined by an A1c <7%. National recognition for hypoglycemic safety is evidenced by the creation of a Health and Human Services Federal Interagency Workgroup (with representatives from VA and DoD) to address adverse drug events, including those from hypoglycemic agents. Moreover, the Choosing Wisely Initiative to reduce low value care led by the American Board of Internal Medicine Foundation includes an American Geriatric Society recommendation to not treat most persons over 65 years of age with medications to reduce the A1c<7.5%. For most physicians this involves changes to their current clinical practice. VHA's soon to be announced response to the Choosing Wisely Initiative will include hypoglycemic safety as one of its targeted conditions. Our goal is to study the implementation of the Choosing Wisely Initiative as it plays out at the facility and practitioner levels. We will assess the concomitant implementation of processes of reducing clinically inappropriately tight glycemic control (de-implementation) as well as assess the effectiveness of a toolkit being promoted by this initiative. Because focus on this initiative could have the unintended consequence of paying less attention to poor glycemic control (A1c>9%), we will also assess undertreatment. In so doing, we will inform both VHA and the broader federal health community. We propose three specific aims: (1) To assess the overall impact, both intended and unintended, of the Choosing Wisely Initiative to reduce overtreatment of diabetes in especially vulnerable populations; (2) To assess the impact of commitment to quality, teaching intensity, and safety culture on likelihood of overtreatment; and (3) To identify configurations of the implementation strategy (Choosing Wisely toolkit), provider characteristics and organizational level factors that are associated with successful reduction of overtreatment rates by comparing high and low performers. We propose a Type III Hybrid Design that focuses on study of implementation while at the same time observing and gathering information on clinical interventions and outcomes. We take advantage of a natural experiment: the VA national initiative (Choosing Wisely) with its associated toolkit) that will roll out ~April 1, 2014. In addition to using longitudinal data to address the overall impact, this project will advance implementation science by using an innovative mixed methods such as Matrix and Qualitative Comparative Analyses in multi- paradigm approach to examine potential mechanisms to explain the variation in reduction of rates of overtreatment and to contribute to a better understanding of implementation of national dissemination projects and multi-component interventions in complex systems.